Many buildings include several types of alarm systems, such as smoke detectors, fire alarms, burglar alarms, and alarms to indicate that a door is ajar. A building may additionally include other alarms depending on the types of danger that the building is susceptible to, e.g., a tornado alarm or an air raid siren. These alarms are generally stand-alone units (i.e., separate from and not in communication with other systems). The alarms may be powered by their own power supplies, such as replaceable batteries. A light may be included with an alarm. For example, some fire alarms include strobe lights that flash to indicate detected fires.
Additionally, buildings have lighting systems. For example, many commercial buildings include fluorescent lighting fixtures for use with fluorescent tubes, though other types of lighting systems using other types of lights, e.g., incandescent lights, are also occasionally used. Fixtures are typically hard-wired to a power source, such as an electric utility line. Additionally, a back-up power source such as a generator may be employed for use when the electric utility line is not functioning. Operation of the lighting system is generally independent of operation of the alarms. That is, the lighting system may produce a generally constant flux of light so long as a switch controlling the lighting system is in an “on” position regardless of whether one or more of the alarms becomes activated.